The present invention relates generally to inflatable cargo or dunnage air bags, and more particularly to a new and improved abrasion-resistant inflatable cargo or dunnage air bag and a method of manufacturing the same.
Inflatable cargo or dunnage air bags are conventionally used within cargo holds or bays of ships, railroad cars, trucks, airplanes, and the like, in order to brace the cargo loads or prevent inadvertent or undesirable movement of the cargo loads during shipping so as to thereby prevent damage to the cargo loads that would otherwise occur as a result of such unwanted movements thereof. Such cargo bags typically comprise a thermoplastic inflatable bladder which is disposed within an outer bag, formed by means of a plurality of paper plies, paperboard, cardboard, or the like, wherein the outer bag serves to protect the bladder from being punctured or otherwise damaged. The inflatable bladder is provided with an inflation valve which is hermetically sealed with respect to the inflatable bladder and which projects externally of the outer bag so as to permit inflation of the composite cargo bag.
The aforenoted type of air bag is typically manufactured from a predetermined or cut length of multi-layered or multi-ply paper which is then folded upon itself wherein the free ends or sides thereof which are being folded toward each other are then overlapped and glued together so as to define a longitudinally extending seam along, for example, the centerline of what is now, in effect, a paper tube which is open at its opposite ends. The inflatable bladder is then inserted into the interior space defined by the paper tube, and the previously open ends of the tubes are then folded and sealed in any one of a plurality of modes, such as, for example, sewing or stitching, gluing, and the like.
It has been experienced that the manufacture of such cargo bags can be quite labor-intensive in that the inflatable bladder is sometimes difficult to insert into the interior space defined within the outer multi-walled or multi-ply paper tube. In addition, due to the intensity or difficulty which is often encountered in connection with the insertion of the inflatable bladder within the interior space of the outer paper tube and the resulting fabrication of the composite cargo bag, there is considerable potential that the thermoplastic bladder can be damaged, even slightly, during the necessary handling of the same whereby, ultimately, when the composite cargo bag is inflated, and during use thereof during a cargo load bracing operation, leakage of the bladder, and therefore the composite cargo bag, can occur which of course would lead to failure of the composite bag with respect to its intended purposes and functions in bracing cargo loads.
In order to alleviate such aforenoted difficulties attendant the manufacture of composite inflatable cargo bags, an improved cargo air bag, and a method of manufacturing the same, was developed and is disclosed within U.S. Pat. No. 4,591,519 which issued to Liebel on May 27, 1986. In accordance with such disclosure, the outer paper bag is not formed as a tubular member but is formed from a pair of paperboard sheet members which are then, in effect, sealed around the inflatable bladder which is interposed therebetween. More particularly, with reference being made to FIG. 1, which corresponds to FIG. 2 of the noted patent, the composite cargo bag comprises a first sheet of paperboard 16, and a second sheet of paperboard 24. The first sheet of paperboard 16 is provided with opposite side flap members 18, and opposite end flap members 26. In fabricating the composite cargo air bag, an inflatable bladder 22 is disposed upon the first sheet of paperboard 16, the second sheet of paperboard 24 is then disposed upon the inflatable bladder 22, and the side and end flap members 18 and 26 of the first sheet of paperboard 16 are then folded over and glued upon exterior peripheral surface portions of the second sheet 24 of paperboard.
While the aforenoted patented cargo air bag therefore appears to have resolved or eliminated the problem, attendant the fabrication of the composite air bag, comprising the difficulties of handling the inflatable bladder and the insertion of the same within the conventionally formed outer paperboard or multi-ply paper tube, the manufacturing process of the patented cargo air bag nevertheless requires substantial handling of the inflatable bladder 22 during, for example, the positioning or disposition of the same with respect to the first sheet of paperboard 16. In addition, the second sheet of paperboard 24 must then be positioned upon or over, or moved relative to, the inflatable bladder 22 Consequently, real potential still exists with respect to possible damage to the bladder, as a result of such handling of the same, or in connection with the handling of the sheets of paperboard with respect to the bladder, during the manufacture of the composite air bag, whereby, as has been noted, potential leakage of the bladder, and of the composite air bag, which, in turn, can lead to failure of the composite cargo air bag, can undesirably occur during a cargo load bracing operation.
A need therefore exists in the art for an abrasion-resistant inflatable cargo air bag which is relatively easy to manufacture whereby the overall productivity thereof is enhanced, and in addition, which will eliminate or significantly minimize the amount of handling required in connection with the thermoplastic inflatable bladder during the manufacture or fabrication of the composite abrasion resistant cargo air bag so as to significantly reduce leakage of the bladder, and the composite cargo bag, and thereby, in turn, eliminate or reduce the possibility of, or potential for, failure of the composite cargo air bag during a cargo load bracing operation.
Accordingly, it is an object of the present invention to provide a new and improved abrasion-resistant inflatable cargo air bag, and a method of fabricating the same, which overcomes the various drawbacks characteristic of the prior art.
Another object of the present invention is to provide a new and improved abrasion-resistant, inflatable cargo air bag, and a method of manufacturing the same, wherein the method of manufacturing the composite, abrasion-resistant inflatable cargo air bag is relatively simple so as to enable productivity thereof to be substantially enhanced.
A further object of the present invention is to provide a new and improved abrasion-resistant, inflatable cargo air bag, and a method of manufacturing the same, wherein the method of manufacturing the composite, abrasion-resistant, inflatable cargo air bag significantly reduces or minimizes the amount of handling of the thermoplastic inflatable bladder required in connection with the fabrication of the composite abrasion-resistant cargo air bag whereby the possibility of, or potential for, damage to the bladder, and in turn, ultimate failure of the composite air bag during a cargo load bracing operation, is significantly reduced.
The foregoing and other objects are achieved in accordance with the teachings of the present invention through the provision of a new and improved composite, abrasion-resistant, inflatable cargo air bag which comprises a liner board, paperboard, or cardboard tube within which a tubular inflatable thermoplastic bladder is already disposed as a result of the composite air bag structure, comprising the tubular liner board and tubular inflatable bladder, being so formed by means of a suitable tuber or tube-forming apparatus or machine. Consequently, at this point in time, the opposite ends of both the outer, tubular liner board, and the inner, tubular thermoplastic inflatable bladder, are open and must be sealed. As a result of the disposition of the inner, tubular thermoplastic inflatable bladder within the outer, tubular liner board, however, a main objective of the present invention is readily and automatically achieved to the effect that the thermoplastic inflatable bladder is not manually handled separately from the outer, tubular liner board, and in addition, opposite surfaces of the thermoplastic inflatable bladder are protected by the upper and lower sections of the outer, tubular liner board.
The opposite open ends of the thermoplastic inflatable bladder are then heat-sealed by any suitable means, and in accordance with one of the significantly new and novel features of the present invention, end caps or end pieces, fabricated from liner board which is similar to the material comprising the outer, tubular liner board of the composite cargo air bag, are mounted upon the open ends of the outer, tubular liner board and sealed thereto by means of a suitable hot melt adhesive, cold glue, or a combination thereof.